Machine-switching telephone-exchange system.



A. E. LUNDELL.

MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

' APPLICATION FILED AUGJZ. I916. 1,29,15,

Patented D60. 4, 1917.

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'MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED AUGJZ. l9l6.

Patented Dec. 4, 1917.

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ALBEN E. LUN DELL, OF NEW YORK, N. Y., ASSIGNOE T0 WESTERN ELECTRIC COMPANY,

1 INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MACHINE-SWITCHING TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Dec. 4, 1917.

Application filed August 22, 1916. Serial No. 116,249.

To all whom it may concern: 1

Be it known that I, ALBEN E. LUNDELL, a' citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Machine-Switching Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relatesto machine switching telephone exchange systems wherein the switches are controlled by revertive 1mpulses.

Its object is to provide a simplified selector circuit arrangement for such systems.

The invention consists in employing, in a system of the revertive-impulse. type, the well-known side switch escapement magnet also as the line relay which controls the application of power to the brush shaft of the switch.

Referring to the drawings, Figure 1 shows the invention embodied in a selector of the step-by-step type, and Fig. 2 shows the invention embodied in a selector of the power driven type;

Referring to Fig. 1, only so much of the sender circuitis shown as is necessary for a comprehension of the invention, since such circuits are well-known; see, for example, Patent No. 1,168,319.

In the system of the patent mentioned, the calling subscriber initiates a call by removing his receiver, and his line, through the intermediation of suitable apparatus, is connected with an operator, who inquires the number wanted and registers it on the key-' board ofher sender. The number is then recorded 0n the register controller associated with the sender and the selectors are controlled in accordance with the condition of the set register controller. Assume, therefore, that the register controller has been set and the operator has depressed the starting key. The depressiongof this key causes the closure ofsequence switch contact 110 at the sender. The closure of this contact completes the following circuit known as the fundamental circiut to initiate group selectioni free pole of battery, side switch escapement magnet 111, conductor 112, side switch arm 113 and its first cont-act, conductors 114, 115, stepping relay 116, sender sequence switch contact 110,conductors 117, 118, side switch arm 119 to ground. Side ture, includes the primary magnet PM in' circuit with an interruptingmachine .120,

over the following circuit: free pole of battery, interrupter 120, magnet PM, conductor 121, side switch arm 122 and its first contact,- armature and'front contact of magnet 111 to ground. The armature 123 of the magnet PM is pivoted at 162, and at one end carries a pawl 1241, which engages a ratchet wheel 125 carried by a rotatable member 126, normally held under tension by'a spiral spring 127 This member 126 carries a gear 128, intermeshing with a gear 129 on'a brush carrier 130, adapted to rotate in bearings 131,132.

Each time the primary magnet PM attracts its armature, an insulated projection 173 carried by arm 133 of said armature closes together springs 134:, 135, thus completing a shunt of the stepping relay 116 at the sender. Then the stepping relay 116' has been operated a sufficient number of times to restore the sender, contact 110 is opened, as described in the patent referred to, whereupon escape magnet 111 becomes de'e'nergized and opens the driving circuit of magnet PM. At this time a set of brushes 141, 146 andl4=7 is positioned just below the desired group of trunks t. The escape magnet 111, in retracting its armature, passes the side switch to the second position in the well-known manner. In position 2, the secondary magnet SM is included in circuit with the interrupting machine 136 to drive the positioned set of brushes over the terminals of the selected group. This circuit is as follows: free pole of battery, interrupter 136, magnet SM, conductor 137, side switch arm 138 and its second contact, conductor 139, armature and back contact of escape magnet 111 to ground. Upon the first upward step of the brush shaft 130, a pin 161, carried by a spring 165, having a tendency to move upwardly, rises into engagement with the notch 166 just above it at the end of the primary selecting movement, and thus locks the member 126 under tension.

In position 2, the side switch arm 140 connects the escape magnet 111 in circuit with the test brushes 141. The test terminals 142 of idle trunks are grounded. When test brush 14:1 encounters a grounded test termi nal 142, escape magnet 111 becomes energized over the following circuit: free pole of battery, magnet 111, conductor 144, side switch arm 140 and its second contact, conductor 145, test brush 141 to grounded test terminal 142. The magnet 111 in attracting its armature, opens the stepping circuit of the secondary magnet SM just traced, thus stopping the selector shaft 130 with the ing of an idle trunk causes a circuitchange to take place at the sender, the sequence switch of which again closes its contact 110 to control the'selecting action of the next selector or connector, as the case may be.

The release of the selector is effected by the grounding of the test conductor 154 which occurs when the subscribers replace their receivers upon the switch-hooks. The groundingof this conductor closes the following circuit, including the release magnet 150': free pole of battery, magnet 150, conductor 155, side switch arm 140 and its third contact, conductor 145, test brushes 141, test terminal 142 to grounded conductor 154. In parallel with the circuit just traced, a circuit is closed for the release magnet of the finder (not shown), said circuit including the offnormal springs 156, 168, conductor 172, side switch arm 1 51 and its third contact, and conductor 153 leading to battery through the release magnet of the finder. Release magnet 150, in attracting its armature, retracts the holding pawl 157 of the ratchet 158, and the holding pawl 159 of rotary ratchet wheel 125, and locks itself over the following circuit: free pole of battery, magnet 150, conductor 155, off-normal springs 156, 168, conductor 172, contact springs 164, 163 to ground. The withdrawal of the pawl 157 permits the brush shaft 130 to drop to its normal position, at which time the gears 129 and 128 will re'e'ngage. The shoulder 170 on the gear wheel 129 forces tooth 161 out of engagement with gear wheel 128, whereupon the spring 127 rotates the member 126 to normal position. The member 126, in restoring, also restores the brush shaft 130 through gears 128 and 129. IVhen the shaft 130 reaches its normal position, springs 156, 168 are opened, which opens the locking circuit of release magnet 150, which, in retracting its armature, permits the pawls 157 and 159 to reengage the ratchets 1'58 and 125 respectively.

Referring now to Fig. 2, which shows the magnet 211 over the following circuit; free pole of battery, magnet 211, conductors 212, 213, side switch arm 214, conductors 215, 216, stepping relay 217, sender sequence switch contact 210, conductorsi218, 219, sidef switch arm 220 and its first contact to ground.

forces the brush carrier 221 into contact with aconstantly moving power shaft 225, to drive the brush carrier 221 upwardly. During the upward movement of the brush carrier 221, the commutator brush 224 wipes over commutator segments 222 once for each group of terminals passed over. Each time. the brush 224 encounters one of saldsegg ments, the stepping relay 217 at the sender is shunted, the shunt circuit leading over conductor 223, commutator segments 222, brush 224 to ground. After thestepping re lay 217 operates a predetermined number of times, the sequence switch contact 210 opens, thus deenergizing the escape magnet 211, which, in retracting its armature, opens the circuit of power magnet P M ,thus stopping the upward movement of the brush carrier 221 just below the desired trunk group. The carrier 221 is held elevated by a finger 246 pivoted to the armature 247 of release magnet 287 engaging an opening in the carrier 221. The escape magnet 211, in deenergiz'ing, releases theside switch into position 2 in the well-known manner. In position 2 of the side switch, arm 226 closes the circuit of secondary magnet S M this circuit including the armature and back con tact of the escape magnet 211. The magnet S t P in attracting its armature, forces the brush carrier 221 against the constantly moving power shaft 227, which elevates the carrier 221 at a lower rate of speed than did the shaft 225. In position 2 of the side switch, arm 228 connects the escape magnet 211 to the test brush 229. Idle trunks are those upon whose test terminals 230 ground is present. When the test brush 229 encounters a grounded test terminal 230, escape magnet 211 energizes over the following circuit: free pole of battery, magnet 211, conductors 212, 231, arm 228 and its second contact, conductor 232, brushes 229 to grounded terminal 230. Magnet 211, in at tracting its armature, opens the circuit of secondary magnet S M thus stopping the brush carrier 221 with the brushes 233, 229, 234 in engagement with the terminals 235, 230, 236 of the seized trunk. in which position it is held by finger 246 engaging an Magnet 211, in attracting its are mature, closes the c1rcu1t of the primary mags, net P M Wl11Cl1, 1n attractlng its armature,

opening in the carrier 221. Escape magnet 211 is constructed and arranged to release the side switch from position 2 into position 3, upon its energization. In position 3 the stepping relay 217 at the sender is extended to the next selector. Side switch arm 228, in position 3, connects the release magnet 237 to the test conductor 238, leading to the next selector, and side switch arm 239,in position 3, connects the test conductor 240 to test conductor 241, leading back to the re lease magnet of the finder.

Upon the replacement of the receivers by the parties to the connection a ground is applied to the test conductor 238, which causes the energization of the release magnet 237 over the following circuit: free pole of battery, magnet 237, conductors 242, 243, side switch arm 228 and its third contact, conductors 244, 232, test brush 229, test terminal 230, to the grounded conductor 238. This ground is also extended to conductor 240 leading back to the finder release 1nagnet over off-normal contact 245. Magnet 237, in attracting its armatures, releases the brush carrier, and locks itself over a circuit including off normal contact 245, which opens when the brush carrier reaches its I normal position.

tor wherein said lines terminate, a side switch for said selector including a control magnet, a revertively controlled sender including a stepping relay, a fundamental circuit including said control magnet and stepping relay and closed under control of said sender, driving means for said selector actuated upon the energization of said con trol magnet, means actuated by the movement of the selector adapted to operate said stepping relay to cause said sender to measure off the travel of said selector, means controlled by said sender when restored for opening said fundamental circuit, and means actuated by the denergization of said control magnet for disabling said driving means and advancing the side switch.

2. In a telephone exchange system, the combination with telephone lines, a selector wherein said lines terminate, a side switch for said selector including an escapement magnet, a revertively controlled sender including a stepping relay, a fundamental circuit including said escapement magnet and stepping relay and closed under control of said sender, a constantly rotating driving shaft, means actuated upon the energization of said escapement magnet adapted to couple said selector to said shaft, means actuated by the movement of the selector adapted to shunt said stepping relay intermittently to cause said sender to measure off the travel of said selector, means controlled by said sender when restored for opening said fundamental circuit, and means for disconnecting said selector from said shaft and for advancing the side switch.

In witness whereof, I hereunto subscribe my name this 21st day of August, A. D.,

ALBEN E. LUNDELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

